<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox" :checked="isAll" @click="handleCheckAll"/>
    </label>
    <span>
      <span>已完成{{doneCount}}</span> / 全部{{total}}
    </span>
    <button class="btn btn-danger" @click="handleClearAllDone">清除已完成任务</button>
  </div>
</template>

<script>
  export default {
    name:'Footer',
    props:['todos','checkAllTodo','clearAllDone'],
    computed:{
      // 总数
      total(){
        return this.todos.length
      },
      // 已完成的总数
      doneCount(){
        let n = 0
        this.todos.forEach(item => {
          if(item.done){
            n+=1
          }
        });
        return n
      },
      // 是否全选
      isAll(){
        return this.todos.every((item)=>{
          return item.done
        })
      }
    },
    methods:{
      // 全选按钮的回调
      handleCheckAll(event){
        // console.log(event.target.checked)
        this.checkAllTodo(event.target.checked)
      },
      // 点击清除已完成按钮的回调
      handleClearAllDone(){
        if(confirm('确定要删除所有已完成的吗？')){
          this.clearAllDone()
        }
      }
    },
  }
</script>

<style scoped>
  /*footer*/
  .todo-footer {
    height: 40px;
    line-height: 40px;
    padding-left: 6px;
    margin-top: 5px;
  }

  .todo-footer label {
    display: inline-block;
    margin-right: 20px;
    cursor: pointer;
  }

  .todo-footer label input {
    position: relative;
    top: -1px;
    vertical-align: middle;
    margin-right: 5px;
  }

  .todo-footer button {
    float: right;
    margin-top: 5px;
  }
</style>